| Least Misty car ever!!
My MINI, even with the aircon off, mists up less than any car I've ever driven. I also live in Scotland - its often cold, and often wet, and yet I've NEVER used the rear screen demister except when its iced up.
I suspect your car may have got damp for some reason...
Also - the main reason I got aircon was for the pouring wet days we get here when 2 warm people with wet coats get in the car, I just love it when the aircon completely demists the car in seconds... I've never had it before and this alone makes that button worth £600!! | 
